The aim of this proposal is to help support an international symposium (Gordon Research Conference) on "Muscle: Contractile Proteins" to be held July 3-8, 2005 in New London, New Hampshire. This meeting is designed to provide a forum for information exchange that will lead to better integration of knowledge about muscle and motor protein structure and function. The Muscle: Contractile Proteins Gordon Conference serves as a forum for leading scientists to have a multi disciplinary discussion of recent advances to our understanding of the mechanism of muscle contraction and its regulation. The present conference was established in 1970, having its origins in Gordon Research Conferences on muscle that date back to 1966. The Muscle: Contractile Proteins Conference is held every third year, alternating with Motility and Contractile Systems, which focuses on the cytoskeleton, and Muscle: Excitation-Contraction Coupling. In 2005 the Muscle: Contractile Proteins Conference will be held on back-to-back weeks at Colby-Sawyer College with the Motility and Contractile Systems Conference, providing the opportunity for those interested in a wide range of topics in cellular motility to attend both. This will be a transitional conference in that the overall focus of the conference will be divided between the Molecular Basis of Muscle Contraction and the broader topic of the Design and Function of Molecular Motors.